Apparatus for making piano damper blocks and similar parts



March 22, 1966 R, c, FRENCH 3,241,584

APPARATUS FOR MAKING PIANO DAMPER BLOCKS AND SIMILAR PARTS Malt'h 22,1966 R, Q FRENCH 3,241,584

APPARATUS FOR MAKING PIANO DAMPER BLOCKS AND SIMILAR PARTS Filed June19, 1965 2 Sheets-Sheet 2 77E OR @Ww ajfw/ Patented Mar. 22, 1956 iceAPPARATUS FOR MAKING PIANO DAMPER BLOCKS AND SIMILAR PARTS Raymond C.French, Sandwich, Ill., assignor to The Wurlitzer Company, Chicago,Ill., a corporation of Uhio Filed June 19, 1963, Ser. No. 288,972

4 Claims. (Cl. 144-35) This invention relates generally to themanufacture of pianos and analogous musical instruments and relates moreparticularly to the production of such cylindrical piano components asregulating rail button bases and damper blocks.

A piano of either the electronic or the mechanical type comprises a vastnumber of individual components; and while certain of these partspossess intricate shapes which require multiple forming operations,other parts have simple shapes which permit one-step manufacture.Examples of these parts of simple shape include ythe cylindricalcomponents known as regulating rail button bases, damper blocks andplate bushings. In the past, these latter parts have been produced byfeeding a long wooden strip or blank of substantially squarecross-section into a complex of rotating knives in order to make acylindrical rod of appropriate diameter. This rod has thereafter beenrepeatedly cut transversely to produce the finished parts elements. Thisprior art procedure has proved to be slow when viewed in the light ofthe appreciable number of these parts which are required every day in apiano factory. Moreover, the cost of these parts has been comparativelyhigh because only selected pieces of wood are suitable for the originalblank and because several machines are necessary to develop a reasonabledaily output of parts.

Therefore, a general object of the present invention is to provide a newand improved -machine for use in making piano damper blocks and similarparts.

Another object of the invention is to provide such a machine that ischaracterized by high speed production.

Still another object of the invention is to provide a machine for use inmaking piano damper blocks and similar parts in groups rather thanindividually.

A further object of the invention is to provide a machine for use inmaking piano damper blocks and similar parts in an economical manner.

A yet further object of the invention is to provide a machine for use inmaking piano damper blocks and similar parts from short boards thatwould otherwise constitute scrap.

These and other objects and features of the invention will become moreapparent from a consideration of the following disclosure.

A machine in accord with the invention includes a number of hollowrotatable end mills for millingly engaging a parts blank, the axes ofthe mills being disposed in parallel relationship and spaced apart topermit overlapping patterns of milling engagement with the parts blank.The machine of the invention also includes a support for the partsblank, means for incurring relative converging and separating motionbetween the end mills and the support, and means for shifting therelative lateral position of the mills and the support whereby todevelop overlapping patterns of milling engagement between the mills andthe parts blank. The machine of the invention additionally incorporatesa rotary cutting element which is selectively operable in a pathtransverse of said support at the discharge end thereof for severingparts elements that have been generated by the mills from the partsblank.

The invention, both as `to its structure and mode of operation, will bebetter understood by reference to the following disclosure and drawingsforming a part thereof, wherein:

FIG. l is a fragmentary, side elevational view of a portion of a pianoaction mechanism, showing in particular the damper block which is usedin mounting a resilient damper head to a damper lever;

FIG. 2 is a side elevational view of a different segment 0f the pianoaction mechanism of FIG. 1, illustrating in particular a regulating railbutton and its associated components;

FIG. 3 is a perspective view of a machine constructed in compliance withthe principles of the invention for use in making piano damper blocksand similar parts;

FIG. 4 is a -top plan view of the machine of FIG. 3;

FIG. 5 is a side elevational view of the machine of FIG. 3;

FIG. 6 is an elevational view taken substantially along the section 6-6of FIG. 5;

FIG. 7 is a schematic perspective view showing the cutoff saw of themachine of FIGS. 16 operative to sever parts elements generated by theend mills from the parts blank;

FIG. 8 is an enlarged plan view showing the engagement between the millsand the parts blank;

FIG. 9 is an enlarged perspective view of an end mill for use in themachine of FIGS. 3 8; and

FIG. l0 is a perspective view of an alternate end mill which may be usedin the machine of the invention.

Referring now in detail to the drawings and first to FIGS. 1 and 2, apiano action mechanism will be seen indicated generally in the twofigures by the numeral 20. In FIG. 1, the piano action mechanism 20 isshown to include a damper head 22 which includes vertically spaced feltblocks 24; and the damper head 22 is mounted to a damper lever 26 bymeans of a cylindrical damper block 28, a damper wire or rod 30 and aset screw 31 whereby the felt blocks 24 may be swung into selective,damping engagement with a piano string 32. In accordance withconventional practice, the piano string 32 is mounted to a piano frame34, and the damper head 22 is positioned to engage the piano string 32beneath an upper bridge 36 of the frame 34. The damper head 22 isadvantageously attached to the damper block 28 by adhesive or othersuitable means; and in compliance with the invention, the damper block28 is adapted to be fashioned from a solid cylindrical parts elementwhich may be provided with intersecting bores for receiving the damperrod 30 and the set screw 31.

In FIG. 2, the piano action mechanism Ztl is shown to include aswingable whip 38 and a fly or jack 40 that is pivotally mounted to thewhip 38 by a y ilange 42, The fly 40 includes a laterally oifset heelportion 44 which is adapted to engage a regulating rail button 46 uponswingable actuation of the whip 38. The regulating rail button 46 ismounted to a regulating rail 48 by means of an eye screw 50, theregulating rail button 46 comprising a wooden regulating rail buttonbase 52 and a felt pad 54. The regulating rail button base 52 comprisesa shallow cylindrical element or disk which is perforated with a centralbore that serves as a pilot hole for the threaded shank of eye screw5t).

Turning to a consideration of FIGS. 3 and 4, a machine indicatedgenerally by the numeral 56 is shown to be constructed in compliancewith the principles of the invention for making cylindrical parts,elements such as the damper block 28 and the regulating rail button base52. The machine 56 includes a number of hollow end mills 58, a supportarrangement 60 for a parts blank 62, a longitudinal drive 64 forincurring relative converging and separating motion between the mills 58and the support arrangement 6), and a lateral drive 66 for shifting therelative lateral position of the mills 58 and E the support arrangement60. The mills 58 are mounted in a carrier 68 and are adapted to berotated in a common direction by means of a `motor 70 which is mountedin the carrier 68 and which acts through a suitable drive coupling 71.The carrier 68 is slidably mounted on a bridge 72 which, in turn, isslidably mounted in parallel, spaced apart tracks 74 and 76.

Considering FIG. 4 in particular, the lateral drive 66 is seen tocomprise a uid actuated jack 78 having a cylinder 80 which is xed to thebridge 72 by a bracket 82, jack 78 additionally having an extensible andretractable piston 84 which is coupled to the carrier 68 by a bracket86. Jack 78 is thus capable of laterally oscillating the carrier 68between extreme positions shown respectively in solid outline and inbroken outline; and as will be described more fully hereinafter, thislateral shifting of the mills 58 relative to the support arrangement 60enables the mills 58 to develop overlapping patterns of millingengagement with the parts blank 62.

In order to reposition the carrier 68 and therefore the mills 58longitudinally of the machine 56, the drive 64 is arranged to include apair of fluid actuated jacks 88 having cylinders 90 which are fastenedindividually to the tracks 74 and 76. The jacks 88 also includeextensible and retractable pistons 92 which are attached to therespective opposite ends of the bridge 72 by couplings 94. Accordingly,proper actuation of the jacks 90 is capable of reciprocating the bridge72 and thereby the carrier 68 between the extreme longitudinal positionsshown respectively in solid and broken outline. These extreme positionsare associated with cutting penetration of the mills 58 into the partsblank 62 and the withdrawal of the mills from the parts blank.

Continuing with reference to FIGS. 3 and 4, the parts blank 62 is seento comprise a flat rectangular board made up of a number of small boardsor wooden strips 96 which have been edge-glued together, the long axisof the wood strips 96 being generally disposed transverse the long axisof the blank 62. For positioning the parts blank 62, the supportarrangement 611 includes spaced lateral guide bars 98 and 100, anunderlying platform 102, best seen in FIGS. and 6, and overlying guideplates 104.

At the discharge end of the support arrangement 60 a pair of stopmembers 106 are cooperatively Situated to abut the parts blank 62 andposition it in one direction for engagement by the mills 58. The stopmembers 1116 are also arranged to arrest converging motion between themills 58 and the support arrangement 60 in order to determine the lengthof the parts elements generated by the mills from the blank 62. Bumperposts 108 are therefore mounted to the carrier 68 laterally of the mills58 to engage the stop `members 106 for this purpose; and in order tosupport the far end of the parts blank 62 against the cutting advance ofthe mills 58, a backing arrangement indicated in FIGS. 4 and 5 by thenumeral 110 is arranged to include an L-shaped bracket 112 which isseated against the rear end of the parts blank 62 to ride in alongitudinal slot 114 fashioned in the platform 102 as is shown in FIG.6. In order to provide positive backing support for the parts blank 62,the arrangement 110 includes a rearwardly extending bar 116 that isathxed to the bracket 112. The bar 116 is provided with a series ofdepending teeth 118 best seen in FIG. 5; and the backing arrangement 110additionally includes means for advancing the bar 116 and therebyadvancing the parts blank 62 against the stop members 1116. Thisadvancing means includes a fluid actuated jack 120 which incorporates anextensible and retractable piston rod 122, a dog 124 being pivoted tothe free end of piston rod 122 by a bracket 126 and a pivot pin 128.Advantageously, a leaf spring 130 is connected to the bracket 126 tobias the dog 124 into engagement with the teeth according to the showingof FIG. 5. As will be recognized, extension of the piston rod 122 causesthe dog 124 to engage a tooth 118 and thereby advance the parts blanktoward the mills 58; however, retraction of the piston rod 122 resultsin the dog 124- riding over the teeth 118 due to the particular slopewith which the teeth are provided. If desired, an auxiliary pressureplaten may be forcibly urged against the upper surface of parts blank 62to pinch the blank against the platform 102 for holding the same inplace against the advance of the mills 58. A fluid actuated jack 134 maybe provided for proper reciprocation for the platen 132, the platen 132being specifically connected to an extensible and retractable piston rod136 of the jack 134.

With reference to FIG. 9, a mill 58 will be Seen fashioned with cuttingedges 138 at its exposed end surface, and these cuttings edges cooperatewith the hollow character of the mill 58 in generating solid cylindricalparts elements 140 from the parts blank 62 as is shown in FIG. 7. Actionof three parallel disposed mills is shown in FIG. 8, where, it will benoted, the axes of the mills are aligned in a common plane and arespaced apart by a distance such that shifting of the carrier 68 betweenthe full and the dotted line positions of FIG. 4 will shift the millaxes a distance at least equal to the sum of the inside diameter and thewall thickness of the respective mills in order to permit overlappingpatterns of milling engagement with the parts blank 62. One pattern ofsuch milling engagement is shown by the penetrated condition of themills 58 in FIG. 8 and a second, overlapping pattern is indicated inbroken outline in that gure. Returning to FIG. 7, the planar alignmentof the axes of parts element 140 indicates that the overlapping patternof milling engagement has proceeded in a strictly horizontal directionwhereby alternate parts elements 140 are fashioned by the first andsecond patterns of milling engagement respectively. It is recognizedthat other types of overlapping patterns may be developed. Vertically asWell as horizontally overlapping patterns may be developed by addingmeans for vertical relocation of the carrier 63 for example.Furthermore, it is realized that there is a limit to the closeness inthe placement of the drive spindles for the mills 58; and ordinarily,the minimum spindle spacing does not permit close spacing of the partselements 140. By developing overlapping patterns of milling engagement,it is possible to generate parts elements 146 from the spacesinterjacent the first pattern of milling engagement whereby to increasethe eciency of wood utilization and reduce costs.

In order to sever the parts elements 140 from the parts blank 62, themachine 56 includes a cutoff unit which is indicated generally by thenumeral 142 in FIGS. 3 and 5-7. The cutoff unit 142 includes a rotarysaw blade 144 which is selectively operable in a path transverse of thesupport arrangement 60 at the discharge end thereof, saw blade 144 beingspecically lowerable into engagement with the parts blank 62 forsevering the generated parts elements 140 therefrom as is indicated inFIG. 7. Specifically and with reference to FIGS. 3 and 6, the rotary sawblade 144 is mounted on a shaft 146 which cornprises the output shaft ofa speed reducer 148. The speed reducer 148 is rigidly attached to acarriage plate 150, and a suitably energized drive motor 152 is alsomounted to the carriage plate to extend its output shaft 154 intosubstantial parallelism with an input shaft 156 of the speed reducer148. Thus, sprockets 158 and 160` may be mounted on the shafts 156 and154 respectively so that the speed reducer may be drivingly coupled tothe output shaft of motor 152 by an endless chain 162 which is disposedin engagement with the sprockets 158 and 160. In order that the rotarysaw blade 144 may be reciprocated in a generally vertical direction, afluid actuated jack 164 includes an extensible and retractable pistonrod 166 which is connected to the carriage plate 150 by a pivot bracket168. It is recognized that the rotary saw blade 144 may be replaced byaxially spaced tandem saw blades where the axial dimension of the partbeing produced is to be closely controlled. Advantageously, the carriageplate 150 is pivotally secured to a mounting arm 170 which is bolted orotherwise secured to track 74 as is shown in FIG. 6, mounting arm 170extending laterally outwardly and upwardly fr-om the track to positionthe rotary saw blade 144 in generally overlying relationship relative tothe support arrangement 60.

Having thus described one construction of the invention, it is importantnow to state how the illustrated embodiment operates.

Assuming that the parts blank 62 has been advanced into abuttingengagement with the stop members 106 as is shown in FIG. 3, thelongitudinal drive 64 will be actuated t-o converge the carrier 68 andthe support arrangement 60, specifically drawing the carrier 68 towardthe support arrangement to advance the mills 58 into cutting engagementwith the confronting edge surface of the parts blank 62 as is shown inFIGS 4 and 8. When a bumper post 108 engages the corresponding stopmember 106, advance of the mills 58 will be arrested; and thereafter,the longitudinal drive 64 will be actuated to retract the mills byseparating the carrier 68 from its converged position relative to thesupport arrangement 60. Next, the lateral drive 66 will be actuated torelocate the carrier 68 into the position indicated specifically inbroken outline in FIG. 4. From this position, the longitudinal drive 64may be actuated to adv-ance the carrier 68 to-wards the supportarrangement 60 and thereby urge the mills 58 into cutting engagementwith the parts blank 62. This second advance of the mills 58 willgenerate the parts elements indicated in broken outline in FIG. 8.

Upon withdrawal of the mills 58, the jack 164 of cutoff unit 142 will beactuated to lower the rotary saw blade 144 into incising engagement withthe parts blank 62 to sever the several parts elements 140 which havebeen generated by the mills 58. This action of the rotary saw blade 144is suggested in FIG. 7. The saw blade 144 is selected to be of such adiameter that its advance into the parts blank 62 not only severs theparts elements 140 but also the end scraps which are indicated in FIG. 7by the numeral 172, thus squaring the end of the parts blank.

When the rotary saw blad-e 144 has been retracted by proper actuation ofthe jack 164, the jack 120 may be actuated to advance the bar 116 andthereby the parts blank 62. Upon the parts blank 6,2 once again engagingthe stop member 106, the actuation of the jack 120 will be terminatedwhile leaving hold pressure thereon. Under the circumstances wherein thepressure platen 132 is incorporated in the machine 56, the jack 134 willnext be actuated to lower the platen 132 for holding the parts blank 62against the platform 102 to resist shifting of the blank during thecutting advance of mills 58.

In the embodiment of the machine 56 which has been shown and describedwith reference to FIGS. 3-9, the stop members 106 have been selected tobe of comparatively short dimension along the longitudinal axis of themachine whereby to permit a relatively deep penetration of the mills 58into the parts blank 62. The mills 58 may thus generate parts elements140 which are of a corresponding length. This length is suitable to theuse of parts elements 140 for the damper block 28 shown in FIG. l. Onthe other hand, when it is desired to use the machine 56 for makingregulating rail button bases 52, for example, the stop members 106 willbe replaced by stop members having a greater dimension along thelongitudinal axis of the machine whereby to reduce the penetration ofthe mills into the parts blank. In addition, the mills 58 will bereplaced by a mills such as the mill 58a shown in FIG. 10, mill 58ahaving a greater inside diameter than the mills 58 whereby to generate apart of correspondingly greater diameter. Moreover, the mill 58a isfashioned to include a small diameter drill bit 174 which is securedcoaxially with the mill 6 58a for simultaneously boring a pilot hole inthe resultant parts element upon generation thereof by the cutting edges138er. If desired and rather than replace the stop members 106 to adjustthe depth of milling engagement, the bumper posts 108 may be replacedwith bumper posts having a greater length.

Other parts may be made by similar readjustments and replacements ofparts in the machine 56. For example, since plate bushings are of adiameter which is similar to the diameter of the regulating rail buttonbase 52, the same means for controlling the depth of cut may be employedwhen the plate bushings are to be manufactured, however, since platebushings ordinarily do not include pilot holes, mills which do notincorporate an integral, coaxial drill will be used in the latterinstance.

From the foregoing descriptions, it will be apparent that the presentinvention provides a machine which is capable of producing piano partsof simple shape in a Y high speed and economical manner. Morespecifically, the machine of the invention produces parts of thischaracter in groups rather than individually; and moreover, the machineof the invention is capable of using as a starting material short boardsthat would otherwise be scrapped whereby to enhance the economy ofoperation.

Therefore, the specific examples herein shown and described are to beconsidered as being primarily illustrative. Various changes beyond thosedescribed will, no doubt, occur to those skilled in the art; and suchchanges are to be understood as forming a part of this invention insofaras they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. Apparatus for use in making piano damper blocks and similar parts,said apparatus comprising: support means for holding a rectangular partsblank in a pr determined plane; a mill carrier; a plurality of paralleldisposed, hollow rotatable mills for cutting edges at correspondingannular end surfaces and mounted on said carrier with their axes alignedwith said plane for millingly engaging a parts blank at an edge thereofand at the discharge end of said support means in such spaced relationas to traverse a substantial portion of the width of the parts blank;drive means for incurring relative converging and separting motionsbetween said carrier and said support means whereby to generate solidcylindrical parts elements corresponding to the internal dimensions ofthe mills; means for effecting relative transverse shifting between saidcarrier and said support means a predetermined increment to shift themill axes a distance at least equal to the sum of the inside milldiameter and the mill wall thickness for relatively positioning saidcarrier and said support means to enable said drive means to incurrelative converging and separating motions therebetween permittinggeneration of another set of solid cylindrical parts elements inoverlapping patterns of milling engagement; and cutoff means selectivelyoperable in a path transverse of said support means at the dischargeends thereof for severing parts elements generated by said mills fromsaid blank.

2. Apparatus as claimed in claim 1, wherein each of said mills includesa relatively small diameter drill bit secured coaxially thereof forsimultaneously boring a hole in the parts elements while `the same arebeing generated by the cutting edges of the mills.

3. Apparatus as claimed in claim 1, including a stop means at the`discharge end of said support means for arresting converging motionbetween the mills and the support means whereby to determine the lengthof the parts elements generated by the mills.

4. Apparatus as claimed in claim 1, including backing means aligned withsaid support means and said mills for supporting the blank against thecutting advance of the mills.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS Brown 144-113 Stimpson 144-45 Wattie 144-35 X Farnum144-12 Carver 1414*'35 Frevel 145--120 8 2,535,670 12/1950 Croft 144-35X 2,794,469 6/1957 Shortell. 3,130,763 4/1964 Schlosser et al.

5 FOREIGN PATENTS 694,799 7/1953 Great Britain.

WILLIAM W. DYER, JR., Primary Examiner.

LEON PEAR, Examiner.

1. APPARATUS FOR USE IN MAKING PIANO DAMPER BLOCKS AND SIMILAR PARTS, SAID APPARATUS COMPRISING: SUPPORT MEANS FOR HOLDING A RECTANGULAR PARTS BLANK IN A PREDETERMINED PLANE; A MILL CARRIER; A PLURALITY OF PARALLEL DISPOSED, HOLLOW ROTATABLE MILLS FOR CUTTING EDGES AT CORRESPONDING ANNULAR END SURFACES AND MOUNTED ON SAID CARRIER WITH THEIR AXES ALIGNED WITH SAID PLANE FOR MILLINGLY ENGAGING A PARTS BLANK AT AN EDGE THEREOF AND AT THE DISCHARGE END OF SAID SUPPORT MEANS IN SUCH SPACED RELATION AS TO TRAVERSE A SUBSTANTIAL PORTION OF THE WIDTH OF THE PARTS BLANK; DRVIE MEANS FOR INCURRING RELATIVE CONVERGING AND SEPARATING MOTIONS BETWEEN SAID CARRIER AND SAID SUPPORT MEANS WHEREBY TO GENERATE SOLID CYLINDRICAL PARTS ELEMENT CORRESPONDING TO THE INTERNAL DIMENSIONS OF THE MILLS; MEANS FOR EFFECTING RELATIVE TRANSVERSE SHIFTING BETWEEN SAID CARRIER AND SAID SUPPORT MEANS A PREDETERMINED INCREMENT TO SHIFT THE MILL AXES A DISTANCE AT LEAST EQUAL TO THE SUN OF THE INSIDE MILL DIAMETER AND THE MILL WALL THICKNESS FOR RELATIVELY POSITIONING SAID CARRIER AND SAID SUPPORT MEANS TO ENABLE SAID DRIVE MEANS TO INCUR RELATIVE CONVERGING AND SEPARATING MOTIONS THEREBETWEEN PERMITTING GENERATION OF ANOTHER SET OF SOLID CYLINDRICAL PARTS ELEMENTS IN OVERLAPPING PATTERNS OF MILLING ENGAGMENT; AND CUTOFF MEANS SELECTIVELY OPERABLE IN A PATH TRANSVERSE OF SAID SUPPORT MEANS AT THE DISCHARGE ENDS THEREOF FOR SEVERING PARTS ELEMENTS GENERATED BY SAID MILLS FROM SAID BLANK. 